1. Field of the Invention
The present invention relates to a method and an apparatus for preparing the statistics for alarms generated by an apparatus to be managed, and for managing the alarms. An example apparatus to be managed is a semiconductor manufacturing apparatus, for manufacturing or inspecting semiconductors, or a liquid crystal display manufacturing apparatus, for manufacturing or inspecting a liquid crystal display, or an ion beam irradiation apparatus used for these apparatuses.
2. Description of the Related Art
For the management of alarms generated by this apparatus to be managed, in the related-art, cases wherein an alarm was generated are simply added for individual alarms, and either a list, a so-called worst list, is prepared in which individual alarms are presented in order, beginning with the largest number of cases, or an analysis chart is prepared, such as a graph in which percentages are used or a Pareto chart.
Further, as a filtering method for designating, or extracting, data to be used for statistics in cases wherein alarms are generated, normally, filtering according to dates and time ranges has been performed. As another method, a technique for employing a lot ID (lot identification information) to perform filtering had also been proposed (see JP-A-6-332910 (paragraph numbers 0008 and 0012, FIG. 1)).
The related-art alarm management technique has the following problems (1) and (2).    (1) The manner in which the alarm statistics are obtained does not match the purpose.
The purpose for which alarm statistics are obtained is mainly the improvement, by employing the statistics, of the efficiency with which the usage of an apparatus is managed. Various problems, failures and defects that result in a reduction in the usage efficiency are acknowledged as alarms by the user and the supplier of the apparatus. The user or the supplier analyzes the alarm statistics, and prepares countermeasures for the cases, beginning with the one that seems most important, in order to improve the usage efficiency of the apparatus. Therefore, the alarm statistics must be those that reflect, as exactly as possible, the affect each alarm will have on the usage efficiency of the apparatus.
However, since in each alarm case the degree of the affect attained is not shown by the related-art alarm statistics, generally, it is concluded that “the alarm that was generated most frequently is the most important”, which is often not correct. An example of this is shown below.
Assume that, during a specific period of time, the number of cases wherein a specific alarm having an example alarm ID of 1001 was generated is 20 and the length of the average period the apparatus was halted when this alarm was generated is one hour, and that the number of cases for which another alarm having an example alarm ID of 3050 was generated is five and the average period the apparatus was halted when this alarm was generated is 10 hours. And that according to the related-art alarm statistics the alarm having the ID 1001 is regarded as being four times more important. However, during the specific period, since the hours the apparatus was halted while the alarm having the ID 1001 and the alarm having the ID 3050 were generated was 20 hours and 50 hours respectively the alarm having the ID 3050 is 2.5 times sore important than is the alarm having the ID 1001, viewed from the affect produced as it relates to the efficiency attained using the apparatus to be managed.
For this example, an explanation has been given for the analysis of the alarm statistics for improving the usage efficiency of the apparatus to be managed. However, various other purposes can be considered, such as a reduction in the maintenance fee for the apparatus to be managed and a reduction in the number of steps performed by the maintenance person. Depending on these purposes, it will be good for an appropriate method to be available for evaluating the affect; however, the related-art alarm management method for preparing the alarm statistics can not perform such an evaluation process.    (2) Alarm statistics can not be employed for pursuing the cause of the generation of an alarm.
Another problem with the related-art alarm management technique is posed by the function for linking (coupling) the alarm statistics with apparatus data representing the status of an apparatus to be managed. When an important alarm, one for which a countermeasure should be applied, has been generated, this does not automatically mean that the role played by the alarm statistics has been completed. While the ideal is for the alarm statistics to be used for designating the reason behind the generation of the alarm, the use of the related-art alarm statistics is not rendered inappropriate because the linking of alarm data with the apparatus data is not satisfactory.
Relative to this viewpoint, the technique disclosed in JP-A-6-332930, concerning the filtering of alarms using lot IDs, is not satisfactory either. Although the lot IDs are correlated with multiple sets of apparatus data, the lot IDs are not always uniquely coupled with these multiple apparatus data sets. That is, even when there is a corresponding lot ID, the operating parameter for the apparatus is not always the same as when the pertinent lot was processed. More specifically, even when the processing recipe, which is a processing condition for the processing of a specific lot, can be designated in accordance with the ID for this lot, the processing recipe is provided by multiple apparatus operating parameters (can be regarded as apparatus data). Thus, even when several of these operating parameters seem to have contributed to the generation of an alarm, in differing processing recipes, these parameters could have the same value. Therefore, the filtering method for each processing recipe using lot IDs is too inaccurate, and it would be difficult to designate an operating parameter that would cause the alarm to be gen rated.